Mechanical Prop...

A steel wire of length $$4.7\ m$$ and cross-sectional area $$3\times 10^{-6} m^{2}$$ stretches by the same amount as a copper wire of length $$3.5\ m$$ ad cross-sectional area of $$4\times 10^{-6} m^{2}$$ under a given load. The ratio of Young's modulus of steel to that of copper is

A iron bar of length $$l$$ cm and cross section $$A$$ $$cm^2$$ is pulled by a force of $$F$$ dynes iron ends so as to produce an elongation $$\Delta l$$ cm. Which of the following statement is correct?

The longitudinal extension of any elastic material is very small. In order to have an appreciable change, the material must be in the form of 

A $$5\ kg$$ rod of square cross section $$5\ cm$$ on a side and $$1\ m$$ long is pulled along a smooth horizontal surface by a force applied at one end. The rod has a constant acceleration of $$2\ m/s^{2}$$. Determine the elongation in the rod. (Young's modulus of the material of the rod is $$5\times 10^{3} N/m^{9})$$.

A rubber rope of length $$8\ m$$ is hung from the ceiling of a room. What is the increase in length of rope due to its own weight? (Given : Young's modulus of elasticity of rubber $$= 5\times 106\ N/m$$ and density of rubber $$= 1.5\times 10^{3} kg/ m^{3}$$. Take $$g = 10\ m/s^{2})$$.

The valve $$V$$ in the bent tube is initially kept closed. Two soap bubbles $$A$$ (smaller) and $$B$$ (larger) are formed at the two open ends of the tube. $$V$$ is now opened and air can flow freely between the bubbles.

A metal rod of Young's modulus $$2\times 10^{10}Nm^{-2}$$ undergoes an elastic strain of $$0.06\%$$. The energy per unit volume stored in $$Jm^{-3}$$ is 

Uniform rod of mass $$m$$, length $$l$$, area of cross-section $$A$$ has Young's modulus $$Y$$. If it is hanged vertically, elongation under its own weight will be :

Identical springs of steel and sopper $$(Y_s > Y_{cu})$$ are equally stretched. Then

There are two wires of same material and same length while the diameter of second wire is two times the diameter of first wire, then the ratio of extension produced in the wires by applying same load will be